Studies will be done using Technetium (99m-Tc) Pyrophosphate (for infarction), Thallium-201 (201-T1) (for flow), and 99m-Tc albumin (for ventricular wall motion). Other measurements will include creatine phosphokinase (CPK) assays, ST segment elevations, coronary sinus blood flow, regional oxygen and lactate levels, and conventional data from human rightsided monitoring and from angiographic data.